Production of powdered capillary-active sulfuric acid derivatives



Patented Nov. 11, 1952 PRODUCT ON F- POW EBED CA ILLARY ACTIVE sULFUnIG ACID DERIVATIVES Hendrik F. Dammers, Amsterdam, Netherlands, assignor to Shell Development. Company, San Francisco, Gali i, a porati n o Delaware No Dr win A plication Ma ch l 9 .8,..Sor al This invention relates to the manufacture of salts of organic acids having a =-=-SO3H group in the molecule which are surface-active agents suitable for use in Wetting, washing and emulsifying operations. It deals particularly with an improved method of producing compositionsfcontaining such salts in the form of substantially dry, non-coherent powders of relatively uniform, fine particle size.

The great bulk of synthetic detergents now on the market. are salts of organic acids having a -=SO3'H grou which is directly linked to a carbon atom of a hydrophobic group as in the sulfonic acids or is attached to an oxygen atom which is directly linked to a carbon atom of a hydrophobic group as in the sulfuric acid esters. Examples of a number of different salts of this type which can be used in the process ofthe invention and which will be referred to generically hereinafter as sulfonic salts, are given in the November-1947 issue of Chemical Industries, pages 811 to 824;.

A common characteristic of these sulfonate salts as normally produced is that they yield particles having a marked tendency to stick together or agglomerate. This is undesirable, not only because it exerts an unfavorable influence on the appearance of the product since the vas,"- glomerated powder is darker colon but also. because the agglomeration interfered with ac curate dosage of the detergent in use and decreases its rate of solution in solvents. Further.- more, apart f o the f e in di advantages, ons mer prefer pro ts. which ar of t so-.cal1ed free-flowing" type, v

The tendency of the dr pu ve zed sul onato salts. to agglomerate varies according to the ha.- ture and generally also the concentration of the sulfonic acid and/or sulfuric acid ester salt in the powder, The salts of the acid sulfuric acid estorsprodnced by sulfa-ting olefins of 8 to about 20 carbon atoms display this undesirable tenderror in a part u a g de e. T endency of the powders to stick together is generally essin the cas o m u o t su io gte sa ts wi h substan ial mou t of i rgan c sa t. for example, 40%. or more by weight. but even with such mixtures the agglomerating tendency is still substantial and quite undesirable. In fact, it, generally impossible to produce properly non-c e ent p w r a g a h g enough com I tent of sulfonate salt to be a practically effective deter nt r w ttin or emulsify ng a e t by mixing the pulverized sulfonate salts with inorganlc salts.

Now, according to the invention, it has sur- In the Netherlands March 21,

4 C aims. (01. Zak-3)- prisin ly been found that fine pulverized non,

coherent powders having excellent detergent,

wettin em sifying and foamin properties can be obtained. startingv fromdry or substantially dry sulfonic acid or acid sulfuric acid ester salts. r mixt res containing these sulfonate salts. h ch sulfonate. sal s or sulfonate salt-containing mixtures display a tenden y to agglomerats when. in powdered f rmby gr ndi the sulionate alt. or lionat salt-containing mixtur with an added finely divided powder which has little or no tendency to stick to ther- As a dition agents which may be. added. du in rindin oi the sulfonate salt accordin o. the process. of the inventio any substance soli at normal tem erat r and w ch may be di id d into a line powd r wh ch sh ws litt e or: o. tend: ency to a glcmerat ay be considered. These addit on a ents wi l be refe red to ener all her inaft r as non-a lomerat n powders- .AS uch, water-soluble i org s s such as alkali metal, or amm n u su iat s, phosphates or ch orides have special advantages, and of these, the neut al salts are preferred, H w ven, i d sired, one may also use for this purpos su stances why are ins lu i Water! such as ta or aol n, or whic are expans b e h water thout. dissolving in. i such as bento ite or other llo dal clays; na i a l ,v su h subs a c s a a only be used when it is n t ob e o able hat en y o e d at r al o stick together is elimlnatedan effect which is not attained-by simply mixing the bstancess pro ably due tov the a t that e. r u e u a s forme n th g in ngprocess. are co e ed su an ially as ast as ormed with. Pa t c es. of the a g oinsrat ng powder a d h s revents h particle oi su i n ts sa t f rmed in no. the rind g from c mb nin gain. t form large conglomerate and o mi g a c arse prod ct, enerally o a y l wi h on Thscnant ty oi the ad ed ubs ance with which he snl nat s it is t be gro nd o der to attain the reflect; a med at: may va y with n ide limits. according; to. the nature and the compo! sition of the. sulfonate salt and the nature. oi the non-agglomerating powder added thereto. The degree of fineness to which the sulfonate at least 25% by weight, calculated on sulfonate.

salt present, and are generally in excess of this figure. Thus, dry products with a content of about 60% secondary sulfuric acid ester salts may be ground with a quantity of sodium sulfate exceeding 100% (calculated on ester salt) to produce a mixture which does not display any tendency to stick together. In general, however. additions in consequence of which the content of sulfonate salt in the final product falls below about 25% cannot be used.

It has been found that in most cases, when sodium sulfate is used as the substance with which the capillary-active material is ground, vryifavorable results are obtained. Anhydrous sodium-sulfate in the form ofa fine dry powder, as it may, for example, be obtained byatomization-drying of an aqueous sodium sulfate solution, has'been found particularly suitable. This favorable effect is connected with the low apparent specific Weight'of the sodium sulfate powder produced in this manner, as a result of which it will'be easier to attain a homogenous division with, this material in the grinding chamber. In view of this, it is in general particularly advisable to use non-agglomerating powders with a low apparent specific weight, i. e.- from 0.1 to 0.5.

It may, however, be desirable in some cases, as

previously pointed out, to use non-agglomerating powders such as talc or bentonite in place of or in addition to sodium sulfate, since talc, bentonite and the like, which have an even lower tendency to agglomerate than sodium sulfate, are more effective, on an equal weight basis, in preventing the agglomeration of sulfonate salts according to the invention.

The process-according to the invention may be applied to sulfonate salts which have been brought into dry or substantiallydry condition in any suitable manner. It is, however, of particular advantage in the improvement of sulfonate salts obtained by means of the known atomization-drying, followed by compression for raising the apparent specific weight. The products obtained according to theatomization-drying method generally have a very low apparent specific weight, which is undesirable, since the large volume of these products involves high cost of transport. Suchproducts may be converted in any convenient manner into pulverized products with a higher apparent specific weight by compression and subsequent grinding.

'In the process according to the invention, the non-agglomerating powder, by means of which the'tendency of the dry sulfonate salt to stick together is checked, should be added to the latter while it is being ground. If desired, however, a; portion of this non-a glomerating powder may also be first 'mixedwith the sulfonate salt, and the mixture be subsequently ground while adding the remainder. If the dry sulfonate salt taken as starting material is compressed and subsequently ground, the nonagglomerating powder may be added either partly before compression Mills particularly suitable for the grinding are those of the cross-stroke o'r' hammer-stroke type, which apparatus renders it possible to prevent undesirable rises in temperature during the grind- While the process of the invention is, as previously pointed out, of special importance in its application to secondary sulfate acid ester salts derived from higher alkenes because of the greater agglomerating tendency of this type of sufonate salt, the process may also be applied successfully and with advantage to the production of non-coherent powders of other sulfonate salts such, for instance, as primary sulfuric acid ester salts obtained by sulfating higher alcoholswhich may, for example, have been produced by hydrogenation of fatty acids or by oxosynthesis-followed by neutralizatiom or alkyl sulfonic acid salts of eight or more carbon atoms per molecule which may be produced, for example, as described in U. S. Patent 2,276,090 or in other suitable Ways, or soluble salts of alkylated aromatic sulfonic acids of the benzene series such as described in U. S. Patent 2,283,199, or sulfo-succinic acid ester salts and the like.

The process according to the invention is further illustrated with reference to the following examples:

Example I By' atomization-drying of an aqueous secondary sodium alkyl' sulfate solution (obtained by reaction of a Clo-C18 alkene fraction with concentrated sulfuric acid and neutralization of the reaction product with sodium hydroxide), a dry. powder was produced, which contained 60% ester.

salt and 40% sodium sulfate.

This powder, which had an apparent specific weight of 0.1 to 0.2, was converted by compression into a product with a specific weight of 1.2 to 1.3;

The compressed product was then ground in a cross-stroke mill and subsequently mixed with about 70% by weight sodium sulfate produced by atomization-drying (apparent specific weight 0.3) The product thus obtained, which had an ester salt content of 35%; gave rise to a. coarsegrained, light yellow powder, which showed-a strong tendency to stick together and which, on

being sifted on a sieve with 30 meshes to an inch, left behind a residue of 20%.

If, on the other hand, an equal quantity of sodium sulfate was added to the compressed product already during the grinding, a fine powder was obtained, of lighter color than the preceding product, which showed no tendency to conglomerataand on being sifted-on'a sieve with 30' meshes to an inch yielded a residue of only 6%.

Example II A capillary-active product consisting of about 98% of the sodium salt of sulfo-succinic acid dioctyl ester, which formed highly conglomerating grains, on being ground in a cross-stroke 'mill' yielded a perfectly conglomerated mass, not an atom of which passed through a sieve with 30 meshes to an inches.- Mixing 0f the product with bentonite or talc produced hardly any improvement.

By grinding the sodium sulfo-succinic acid 65% by weight talc, respectively. On being sifted on a sieve with 60 meshes to an inch, these products left a residue of only 20% and 13%, respectively.

I claim as my invention:

1. In a process for producing a fine, noncoherent powder of relatively high apparent specific weight from a surface-active salt of an organic acid having a SOsH group, the steps comprising (1) spray-drying an aqueous solution of said salt to produce a dry powder of relatively low apparent specific weight, (2) compressing the spray-dried powder into an agglomerate of relatively high apparent specific weight, (3) adding to the compressed agglomerate a dry powder of the type which retains its powder condition during a grinding operation, and (4) grinding the mixture of agglomerate and added powder to produce. a powder of relatively high apparent specific weight; the amount of said dry powder added in step 3 being equal to at least 20% by weight of said salt but insufiicient to reduce the concentration of said salt in the product to below 25%.

2. A process in accordance with claim 1 wherein the surface-active salt is a water-soluble salt of an alkyl sulfuric acid having 8 to 20 carbon atoms per molecule.

3. A process in accordance with claim 1 wherein the surface-active salt is a water-soluble salt of an alkylated aromatic sulfonic acid of the benzene series.

4. A process in accordance with claim 1 wherein the dry powder is added to the agglomerated surface-active salt at least in part during the said grinding step, said powder being of about to about 300 mesh and having an apparent specific weight of about 0.1 to about 0.5.

HENDRIX F. DAMMERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

1. IN A PROCESS FOR PRODUCING A FINE, NONCOHERENT POWDER OF RELATIVELY HIGH APPARENT SPECIFIC WEIGHT FROM A SURFACE-ACTIVE SALT OF AN ORGANIC ACID HAVING A -SO3H GROUP, THE STEPS COMPRISING (1) SPRAY-DRYING AN AQUEOUS SOLUTION OF SAID SALT TO PRODUCE A DRY POWDER OF RELATIVELY LOW APPARENT SPECIFIC WEIGHT, (2) COMPRESSING THE SPRAY-DRIED POWDER INTO AN AGGLOMERATE OF RELATIVELY HIGH APPARENT SPECIFIC WEIGHT, (3) ADDING TO THE COMPRESSED AGGLOMERATE A DRY POWDER OF THE TYPE WHICH RELTAINS ITS POWDER CONDITION DURING A GRINDING OPERATION, AND (4) GRINDING THE MIXTURE OF AGGLOMERATE AND ADDED POWDER TO PRODUCE A POWDER OF RELATIVELY HIGH APPARENT SPECIFIC WEIGHT; THE AMOUNT OF SAID DRY POWDER ADDED IN STEP 3 BEING EQUAL TO AT LEAST 20% BY WEIGHT OF SAID SALT BUT INSUFFICIENT TO REDUCE THE CONCENTRATION OF SAID SALT IN THE PRODUCT TO BELOW 25%. 